Information detecting system of scanning type

Abstract

Disclosed is an information detecting system of scanning type which comprises a substrate formed with an optical waveguide layer, a laser oscillator emitting a laser beam, a SAW type beam deflecting device formed on the optical waveguide layer, a beam irradiating section irradiating a specimen with the laser beam derived from the optical waveguide layer, a controller controlling the frequency of a high-frequency voltage applied to the SAW type beam deflecting device so as to scan the specimen with the laser beam directed from the beam irradiating section, and a detecting section detecting the position and/or the intensity of the laser beam scanning the specimen with respect to the SAW control signal controlled by the controller.

We claim: 
     
       1. A position information detecting system of scanning type comprising: a laser source;   an optical waveguide layer formed on the substrate, the optical waveguide for propagating a laser beam generated from said laser source;   a laser beam deflecting device of surface acoustic wave type provided on said optical waveguide, said laser beam deflected device for deflecting said laser beam propagated through said optical waveguide in accordance with frequency of an a.c. signal applied;   means for irradiating a deflected laser beam deflected by said laser beam deflecting device and propagated through said optical waveguide so as to scan said deflected laser beam on a specimen having indicia thereon;   photo-detection means for detecting a data output signal by receiving at least one of: a reflected light, a transmitted light or a diffracted light obtained from said indicia by scanning said focused laser beam;   converting means for converting a control signal to said frequency of an a.c. signal; and   position detecting means for detecting position information of said indicia in accordance with a variation of a corrected signal obtained by correcting said data output signal in accordance with a displacement value of said focused laser beam communicated to said converting means by said control signal.   
     
     
       2. A position information detecting system according to claim 1 further comprising: first detecting means for detecting at least intensity of said deflected laser beam; and   first correcting means for correcting said data output signal to said corrected signal in accordance with said intensity of said deflected laser beam detected by said first detecting means such that said corrected signal is stabilized in relation with a scanning amount.   
     
     
       3. A position information detecting system according to claim 2, wherein said first detecting means is located at a position substantially conjugate with respect to said specimen. 
     
     
       4. A position information detecting system according to claim 2, wherein said first detecting means is provided on said substrate. 
     
     
       5. A position information detecting system according to claim 1, wherein said converting means includes a second correcting means for correcting said frequency of an a.c. signal by correction to said control signal to obtain an absolute value of a scanning amount. 
     
     
       6. A position information detecting system according to claim 5 further comprising: a beam deflection angle detection means for detecting a beam deflection value corresponding to a deflection accomplished by said laser beam deflecting device so that said second correcting means corrects said frequency of an a.c. signal in accordance with said beam deflection value detected by said beam deflection angle detection means.   
     
     
       7. A position information detecting system according to claim 1, wherein said irradiating means includes a beam focusing optical means for focusing said deflected laser beam toward and onto said specimen. 
     
     
       8. A position information detecting system according to claim 1, wherein said position detecting means detects the position of the information in the form of a linear pattern provided on said specimen. 
     
     
       9. An information detecting system according to claim 1, wherein said specimen includes a wafer and said indicia is an alignment mark provided thereon so that said information detecting system is used for an alignment optical system for a semiconductor manufacturing apparatus. 
     
     
       10. An information detecting device according to claim 1, wherein said indicia is a bar code and said information detecting device is used for a bar-code reader. 
     
     
       11. An information detecting device according to claim 1, said specimen is inclined relative to a scanning plane so that said information detecting device is used for a height detection apparatus. 
     
     
       12. A position information detecting system according to claim 1 further comprising: a position sensor including means for providing a predetermined position and means for obtaining an absolute origin signal by detection of said reflected laser beam such that the position detecting means detects said position information as absolute information by said absolute origin signal.   
     
     
       13. A position information detecting system according to claim 1, wherein photo-detection means includes means for providing diffracted light generated from a linear pattern provided on said specimen. 
     
     
       14. An information detecting system of scanning type comprising: a substrate formed with an optical guide layer;   a laser oscillator emitting a laser beam;   a beam deflecting device of surface acoustic wave type formed on said optical waveguide layer;   beam focusing and irradiating means for focusing at least part of the laser beam derived from said optical waveguide layer and irradiating a specimen with said focused laser beam;   control means for controlling, in response to a SAW control signal, the frequency of a high-frequency voltage signal applied to said surface acoustic wave type beam deflecting device so as to scan said specimen with said laser beam directed from said beam focusing and irradiating means;   first detecting means for detecting the intensity of said focused laser beam scanning said specimen in response to said surface acoustic wave control signal;   second detecting means for receiving at least one of: a reflected portion, a transmitted portion or a diffracted portion of said focused laser beam scanning said specimen and converting said received beam into a corresponding signal, thereby detecting information provided on said specimen;   correcting means for correcting said signal generated from said second detecting means on the basis of the intensity of said laser beam detected by said first detecting means; and   means for deriving said information on said specimen on the basis of the output signal of said correcting means and aid surface acoustic wave control signal.   
     
     
       15. An information detecting system according to claim 14, wherein said first detecting means includes means for receiving part of said laser beam directed from said beam focusing and irradiating means and, on the basis of said received part of said laser beam, detecting the intensity of said focused laser beam scanning said specimen. 
     
     
       16. An information detecting system according to claim 15, wherein said beam focusing and irradiating means is formed at right angles with respect to the emanating direction of said laser beam and includes an end surface of said substrate provided with a half-mirror coating, and said part of said laser beam is that directed from said beam focusing and irradiating means and reflected from said end surface of said substrate. 
     
     
       17. An information detecting system according to claim 16, further comprising means for successively detecting the position of said laser beam shifted in response to said SAW control signal and correcting means for correcting said control signal on the basis of the difference between the detected beam position and the beam position specified by said control signal and applying said corrected control signal to said control means. 
     
     
       18. An information detecting system according to claim 16, further comprising means for monitoring the output of said control means and correcting means for correcting said control signal on the basis of the difference between the output of said monitoring means and said control signal and applying said corrected control signal to said control means. 
     
     
       19. An information detecting system according to claim 15, wherein said first detecting means includes a sensor array composed of a plurality of photo diodes, and said sensor array receives part of said laser beam directed from said beam focusing and irradiating means, and, on the basis of said received part of said laser beam, detects the position and/or the intensity of said focused laser beam scanning said specimen. 
     
     
       20. An information detecting system according to claim 19, wherein an output of a specific one of said photo diodes constituting said sensor array indicates a particular point. 
     
     
       21. An information detecting system according to claim 20, wherein said particular point is an absolute origin. 
     
     
       22. A position information detecting system of a scanning type comprising: a laser source;   an optical waveguide layer, formed on a substrate, for propagating a laser beam generated from said laser source;   a surface acoustic wave laser beam deflecting device provided on said optical waveguide, said laser beam deflecting device including means for deflecting said laser beam propagated through said optical waveguide in accordance with frequency of an applied a.c. signal;   means for irradiating a deflected laser beam deflected by said laser beam deflecting device and propagated through said optical waveguide so as to communicate said deflected laser beam on a specimen having indicia thereon;   photo-detection means for detecting an electric signal by receiving at least one of: a reflected light, a transmitted light or a diffracted light obtained from said indicia by scanning said focused laser beam;   converting means for converting a control signal to said frequency of an a.c. signal;   first detecting means for detecting at least intensity of said deflected laser beam deflected by said laser beam deflecting device;   first correcting means for correcting said electric signal to said corrected signal in accordance with said intensity of said deflected laser beam detected by said first detecting means so as to obtain said corrected signal stabilized in relation with a scanning amount; and   position detecting means for detecting position information of said indicia in accordance with a variation of a corrected signal obtained by correcting said electric signal in relation with a displacement of said focused laser beam communicated to said converting means by said control signal.   
     
     
       23. A position information detecting system of scanning type comprising: a laser source;   an optical waveguide layer formed on the substrate, the optical waveguide for propagating a laser beam generated from said laser source;   a surface wave acoustic laser beam deflecting device provided on said optical waveguide, said laser beam deflecting device including means for deflecting said laser beam propagated through said optical waveguide in accordance with a frequency of an a.c. signal applied thereto;   means for irradiating a deflected laser beam deflected by said laser beam deflecting device and propagated through said optical waveguide so as to scan said deflected laser beam on a specimen having indicia thereon;   photo-detection means for producing an electric signal by receiving at least one of a reflected light, a transmitted light and a diffracted light obtained from said indicia by scanning said focused laser beam;   converting means for converting a control signal to said frequency of an a.c. signal and provided by a second correcting means for correcting said frequency of an a.c. signal by correcting said control signal so as to obtain an absolute value of a scan signal level; and   position detecting means for detecting position information of said indicia in accordance with a variation of a corrected signal obtained by correcting said electric signal in accordance with said scan signal level of said focused laser beam given to said converting means by said control signal.   
     
     
       24. An alignment optical system for a semiconductor manufacturing apparatus, comprising: illumination means for generating an ultraviolet light to illuminate a reticle;   a projection lens for projecting said light transmitted via said reticle onto a wafer;   a reticle alignment optical system disposed at a location between said illumination means and said projection lens;   a stage disposed at such a location that allows said stage to receive said light from said projection lens, for movably supporting said wafer;   means mounted on said stage for measuring a moved distance of said stage; and   means disposed in a gap between said projection lens and said stage for detecting an alignment mark provided on said wafer;   a laser source;   an optical waveguide layer formed on the substrate, for propagating a laser beam generated from said laser source;   a surface acoustic wave laser beam deflecting device, provided on said optical waveguide, including means for deflecting said laser beam propagated through said optical waveguide in accordance with frequency of an a.c. signal applied thereto;   means for irradiating said wafer with a deflected laser beam deflected by said laser beam deflecting device and propagated through said optical waveguide so as to scan said deflected laser beam on said wafer having alignment indicia disposed thereon;   means for controlling the frequency of said a.c. voltage;   first detection means for detecting position relative to the frequency of said a.c. voltage and intensity of the laser beam irradiating and scanning said wafer;   second detection means for receiving diffraction light from said wafer and converting the received light to an electrical signal to detect information regarding the alignment indicia;   means, connected to said controlling means, for correcting said frequency on the basis of the position of the light detected by said first detection means; and   third detection means for detecting the position of said alignment indicia on the basis of at least said information obtained by said second detection means and said intensity of the light detected by said first detection means.   
     
     
       25. A bar-code reader comprising: means for scannably generating laser light;   means for guiding said laser light from said generating means onto a specimen having a bar code disposed thereon;   first detection means for detecting the laser light after exposure to said specimen;   second detection means for receiving a portion of said laser light generated from said generation means to detect intensity of said generated laser light; and   means for reading said bar code on the basis of outputs of said first and second detection means;   wherein said generation means includes: a laser source,   an optical waveguide laser, formed on a substrate, for propagating a laser beam generated from said laser source,   an acoustic wave type laser beam deflecting means, provided on said optical waveguide, for deflecting said laser beam propagated through said optical waveguide in accordance with frequency of an a.c. signal applied thereto, and   means for controlling the frequency of said a.c. voltage so as to scan said specimen with said deflected laser beam.